Bis-(π-cyclopentadienyldicarbonyliron)(I) is oxidised by an excess of anhydrous ferric perchlorate in acetone, yielding solutions of [(π-C5H5)Fe(CO)2OCMe2]+(IIa), which, on treatment with various ligands, gives complexes of the types [(π-C5H5)Fe(CO)2L]+(II) and (π-C5H5)Fe(CO)2X (III).
